dr_kca
Junior Member level 3
Hi,
I am simulating IBIS model using Mentor Graphic's SPICE simulator ELDO. While testing differential buffers with differential termination at input side, I notice that "R Series" model defined with [Series Pin Mapping] is not detected in this simulator. The simulation behaves like there is no series element defined. I first noticed this while simulating model's that I've developed and assumed that the error is at my side. I then simulated models validated at industrial level and see that they do not work neither in the same simulator. I am only talking for Series model that are mapped in Series Pin Mapping, anything else works fine.
Does anyone have experienced this issue before, if yes any solution ?
I am almost sure how the Series Model is defined is correct but I am sharing since it can help.
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[Series Pin Mapping] pin_2 model_name
10P 10N ODT_RTERM
[Model] ODT_RTERM
Model_type Series
Polarity Non-Inverting
C_comp 0pF 0pF 0pF
[Temperature Range] 25 125 -40
[Voltage Range] 2.5 2.25 2.75
[R Series] 95ohm 105ohm 85ohm
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Pins 10P and 10N are also defined earlier in differential pin list. The differential behavior is working since I see what I expect if I instantiate the physical termination resistance by hand.
Thank you!
- - - Updated - - -
I am updating my thread because I've figured it out what is wrong and maybe it can be useful for someone else in future.
The problem is in my understanding of Series Model. When a series mapping is done between pin X and pin Y , unlike submodels, the series model between pin X and pin Y is not directly called when a differential buffer with pin X and pin Y is instantiated. One should instantiate the Series Model as a separate buffer in the netlist.
I am simulating IBIS model using Mentor Graphic's SPICE simulator ELDO. While testing differential buffers with differential termination at input side, I notice that "R Series" model defined with [Series Pin Mapping] is not detected in this simulator. The simulation behaves like there is no series element defined. I first noticed this while simulating model's that I've developed and assumed that the error is at my side. I then simulated models validated at industrial level and see that they do not work neither in the same simulator. I am only talking for Series model that are mapped in Series Pin Mapping, anything else works fine.
Does anyone have experienced this issue before, if yes any solution ?
I am almost sure how the Series Model is defined is correct but I am sharing since it can help.
-----
[Series Pin Mapping] pin_2 model_name
10P 10N ODT_RTERM
[Model] ODT_RTERM
Model_type Series
Polarity Non-Inverting
C_comp 0pF 0pF 0pF
[Temperature Range] 25 125 -40
[Voltage Range] 2.5 2.25 2.75
[R Series] 95ohm 105ohm 85ohm
-----
Pins 10P and 10N are also defined earlier in differential pin list. The differential behavior is working since I see what I expect if I instantiate the physical termination resistance by hand.
Thank you!
- - - Updated - - -
I am updating my thread because I've figured it out what is wrong and maybe it can be useful for someone else in future.
The problem is in my understanding of Series Model. When a series mapping is done between pin X and pin Y , unlike submodels, the series model between pin X and pin Y is not directly called when a differential buffer with pin X and pin Y is instantiated. One should instantiate the Series Model as a separate buffer in the netlist.